How to check if a variable is None in Python
In this tutorial, we are going to learn about how to check if a variable is None or not in Python with the help of examples.
Note: None means null value in Python.
Consider, that we have the following variable in our code:
x = None
Now, we need to check if the above variable is None or not.
Using is keyword
To check if a variable is None or not, we can use the
is keyword in Python.
is keyword returns True, if the both values refers to the same object. Otherwise, it returns false.
Here is an example:
x = None if x is None: print('Variable is None') else: print('Variable is not None')
'Variable is None'
In the above code,
We have first initialized a variable with a None value.
Then we used
iskeyword to check if both values refers to same object.
If it returns
True it prints the
variable is None, if variable is not None then it returns
False and prints
Variable is not None.
y = 10 if y is None: print('Variable is None') else: print('Variable is not None')
'Variable is not None'
Similarly, we can also use the
isinstance() function in Python to check if a given variable is None.
x = None if isinstance(x, type(None)): print('Variable is None') else: print('Variable is not None')
isinstance() function takes the two arguments, the first argument is
object, and the second argument is
type then It returns
True if a given object is a specified type otherwise it returns